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40 Cards in this Set
- Front
- Back
CHF is a syndrome comprising abnormal left ventricular function and neurohormomal regulation accompanied by which three things
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effort intolerance
fluid retention decreased longevity |
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what are the four stages of treatment of CHF
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1. prevention of heart failure
2. treatment to prolong life 3. treatment to reduce sx 4. end-stage considerations |
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what are the two major consequences of LV dysfunction
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decreased CO
venous congestion |
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the decreased CO resulting in reduced delivery of oxygenated blood to the vital organs and skeletal muscle is often called...
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forward failure
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what are the manifestations of forward failure
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DEC EXERCISE TOLERANCE
inc fatigue dec renal perfusion w/ azotemia cachexia hypotension |
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less blood being pumped out of the ventricle resulting in more left behind in the atrium, resulting in increased venous pressure and congestion is called...
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backward failure
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what else contributes to backward failure
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compensatory neurohumoral response- it causes Na/fluid retention
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what are manifestations of backward failure
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atrial enlargement (-> cause a-fib)
thromboembolism (venous stasis) edema dyspnea hypoxemia hypoxia |
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what four independent factors determine left ventricular performance
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preload
afterload contractility heart rate and rhythm |
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what is preload
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the tension in the ventricle at end diastole
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what does excess preload cause
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venous congestion- diuretics, nitrates, morphine, Na restriction, water restriction are all effective
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What is the traditional mainstay of therapy for those with intractable fluid overload and was shown by the RALES trial to also reduce mortality
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loop diuretics like furosemide are traditional
potassium sparing diuretics like spironolactone are also good |
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what type of drug can reduce excess preload indirectly by improving forward flow through the ventricle
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ACEI
or DIGOXIN |
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what can excessive diuretic use cause
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dehydration -> inadequate preload and forward failure
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what is afterload
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the wall stress during systole, largely determined by systolic blood pressure
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what is the vicious cycle of afterload?
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severe hypertension -> chronic excess afterload -> reduced CO -> compensatory neurohumoral response -> increased afterload -> worsened systolic heart function -> reduced CO ...
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what can break the vicious afterload cycle by reducing the neurohumoral response and lowering afterload, causing improved cardiac function and less venous congestion
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ACEI
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what is contractility
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the squeezing strength of the pump
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what is systolic dysfunction
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ejection fraction <45%
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What are the most common causes of reduced contractility
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MI and idiopathic dilated cardiomyopathy
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Name four classes/drugs that directly improve systolic function
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DIGOXIN
beta agonists (DA, dobutamine) phophodiseterase inhibitors vesnarinone |
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Why is digoxin the only drug used to directly improve systolic function
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the others INC mortality in clinical trials despite improving symptoms
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What is the short term and long term effect of beta blockers on contractility
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short term reduction
chronic response is INCREASED ejection fraction |
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What do calcium channel blockers do to contractility
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(except amlodipine) they reduce contractility, leading to increased mortality in patients with systolic dysfunction
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can abnormally increased contractility cause heart failure
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yes- concentric LV hypertrophy; hypertrophic cardiomyopathy
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how many CHF patients have a defect in diastolic function
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1/3
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what is diastolic dysfunction often called
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little old lady's heart
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What is frequently presribed for diastolic dysfunction
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negative inotropes like beta blockers and verapamil
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what is the term when excessive afterload reduction causes a situation where the ventricle completely empties at end-systole -> precipitating syncope due to reflex bradycardia (Bezold-Jarisch response) or pulmonary edema due to extreme tachycardia
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cavity obliteration
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Systolic dysfuction:
dPdT Ejection fraction chamber volumes LV diastolic pressure etiologies |
dPdT- dec dec
Ejection fraction- dec dec chamber volumes- inc inc Lv diastolic pressure- inc etiologies- ischemia, hypertension, idoipathic, toxin (EtOH), infection (chagas) |
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diastolic dysfunction:
dPdT Ejection fraction chamber volumes LV diastolic pressure etiologies |
dPdT- inc
ejection fraction- inc inc chamber volumes- dec LV diastolic pressure- inc etiologies- hypertension, HOCM |
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Systolic dysfunction:
ACE inhibitors CCB beta blockers diuretics digoxin |
ACE inhibitors- YES- 1ST LINE
CCB- CONTRAINDICATED (except amlodipine) beta blockers- ok diuretics- spironolactone DIGOXIN- yep |
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diastolic dysfunction:
ACE inhibitors CCB beta blockers diuretics digoxin |
ACEI- if BP elevated
CCB- verapamil beta blockers- YES,esp w/ angina diuretics- beware hypotension digoxin- CONTRAINDICATED |
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What do you do for chronic symptomatic bradycardia
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pacemaker- there is no drug therapy
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What do you do for acute bradycardia
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atropine if excess vagal tone is the problem
or beta agonist- dobutamine, epi |
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chronic tachycardia reduces cardiac output by limiting __ filling and can eventually cause severe __ dysfunction
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diastolic
systolic |
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what is an underecognizaed cause of CHF
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a-fib
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what is the drug of choice for maintaining sinus rhythm in heart failure
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amiodarone
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what can control ventricular rate in a-fib
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digoxin
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what do you do for patietns with tachycardia that can't be controlled with drugs
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surgical ablation of the AV node
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